LED Substrate Roughening and Light Shielding for Color Mixing
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Solution Overview
Problem
Light emitting diodes (LEDs) used in display devices face challenges with color mixing due to their miniaturization, leading to inefficiencies in light extraction and distribution, particularly in backlight applications where neighboring cells may interfere with each other's light emission.
Innovation Solution
A light emitting device design featuring a substrate with a rough surface on one side and a light shielding layer on the other, which includes a convex and concave pattern to diffuse and extract light efficiently, preventing color mixing by using a combination of first and second light shielding layers to manage light emission from multiple LEDs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If light emitting diodes are miniaturized for display devices, then device compactness is improved, but color mixing between neighboring cells occurs
Solution Approach 1:
The patent introduces light shielding layers that segment the light paths between neighboring LED cells. These shielding structures divide the optical space, preventing light from one cell from interfering with adjacent cells, thereby resolving the color mixing issue while maintaining miniaturization.
Solution Approach 2:
The patent applies different surface properties to different regions: the light extraction surface has a rough texture to enhance light extraction efficiency, while light shielding layers are positioned in specific locations to block harmful light. This local differentiation allows compact design without color mixing.
2Illumination intensity
If light extraction efficiency is increased through rough surface treatment, then light output is improved, but device complexity increases
Solution Approach 1:
The patent employs a rough surface texture on the light extraction surface, utilizing curved and irregular surface geometry to scatter and extract light more efficiently. This curvature-based approach enhances light output without requiring complex internal structures or additional components.
3Manufacturing precision
If light shielding layers are added to prevent color mixing, then color reproducibility is improved, but manufacturing complexity increases
Solution Approach 1:
The patent combines multiple functions into the light shielding layers: they serve as both optical shields to prevent color mixing and as structural elements that define device geometry. This merging reduces the need for separate components, simplifying manufacturing despite the added functional requirements.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The design enhances light extraction efficiency, reduces color mixing, and improves contrast and color reproducibility by diffusively reflecting and shielding light, thereby optimizing the performance of LEDs in display devices.
Implementation Method 1
the second surface of the substrate has a rough surface that overlaps at least a portion the light emitting area
Data Source
AI summary
A light emitting device including a substrate having a light emitting area and a light shielding area, a light emitting structure disposed on the substrate and comprising at least one active layer, and a light shielding layer disposed on the substrate and defining the light shielding area, in which the light emitting area overlaps with the light emitting structure, the substrate has a rough surface overlapping at least a portion of the light emitting area, and a portion of the rough surface is covered with the light shielding layer, and light emitted from the at least one active layer is configured to be transmitted through the substrate.